Performance of Continuous FI Based Assays
Operating flow injection at constant continuous flow, the legacy of Auto Analyzer, is the simples option, and this is why cFI has such an immense appeal, and why this method found a wide range of applications. The most frequently analyzed species, listed in this table represent only a fraction  of  a  broad variety of analytes. Thus Method list of Lachat Co comprises over eighty analytes, determined in a wide variety of  sample materials by cFI. Search of Hansenís Bibliography will yield information on assay of thousands of analytes, automated by FI or by  SI.

Concentration ranges, shown in  this table, obtained with the spectrophotometric detection, are extended down to ppb  level, by using long light path flow cell, and by optimizing conditions for the chemical reactions. Since increase  of sensitivity is  obtained by prolonging the incubation period, sampling frequency at sub ppm level is lower, at about 1 sample per minute

Claims of LOD below 1 ppB P have been made (for applications in oceanography) when using 1 m long flow cell and sampling rates of 6s/hr. Preconcentration of target analyte and matrix removal using micro columns embedded into the flow path is yet  another option to increase selectivity and sensitivity of cFI based assay.
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1.2.20.